This invention relates to an electrophoretic apparatus, particularly one which employs a gel as a medium.
There is known an electrophoretic process which employs a slab or capillary gel for determining the sequence of bases in DNA. The sequence of bases in DNA is determined by the Sanger method which employs an M13 vector, or plamsmid PUC. The Sanger method which employs plasmid PUC, however, often makes it difficult to decode the sequence of bases in DNA correctly because of the stacking of DNA's modified by plasmid PUC and having a single strand.
There has, therefore, been proposed a process which employs the Sanger method with the PCR method which employs polymerase having a high temperature. DNA is thermally modified into single-strand, or template DNA, and a primer is annealed onto the template DNA. Then, the Sanger method is applied to the template DNA to synthesize thereon a complementary DNA fragment of any length ending with four different kinds of bases. The PCR method is applied to the template DNA on which the complementary DNA fragment has been formed, so that the template DNA may be separated from the complementary DNA fragment. The annealing of the primer onto the template DNA, and the Sanger and PCR methods are repeated several tens of times to produce a large amount of complementary DNA fragments, whereby an improved accuracy of electrophoretic identification can be achieved to determine the sequence of bases in DNA correctly.
In the process which employs the Sanger method in combination with the PCR method, however, the electrophoretic operation is completely separated from the treatment of a sample by the Sanger method. The sample is treated by the Sanger method, and is transferred by a pipette, or the like to a electrophoretic apparatus. As there is no alternative but to do any such work manually, the above process cannot automatically determine the sequence of bases in DNA.